1. Technical Field
The disclosure relates to a driving interface device adapted to a flat speaker.
2. Technical Art
A visual sense and a hearing sense are two most direct senses of mankind. For a long time, scientists have tried to develop various renewable visual sense and hearing sense systems. At present, the market is mainly dominated by moving-coil speakers. In recent years, along with a rising requirement for sensory quality, and under a premise that 3C products (computer, communication, consumer electronics) pursue design features of lightness, slimness, shortness and smallness, a power-saving and light and slim speaker designed according to ergonomics is developed, which can be applied to either large-size flat speakers, or small-size earphones of walkmans and stereo mobile phones. In the foreseeable future, such technique may have growing application demands and rapid development.
Electroacoustic speakers are mainly grouped into direct radial and indirect radial electroacoustic speakers, and according to driving methods of the speakers, the speakers mainly catalogued as moving-coil, piezoelectric or electrostatic speakers. The moving-coil speaker is a commonly-used type products with mature techniques, though due to its inherent structural shortage, it cannot be flattened, so that under developing trends of miniaturization of the 3C products and flattening of home theatres, applications of the moving-coil speakers are limited and do not meet the requirements of design features.
Regarding the piezoelectric speaker, based on a piezoelectric effect of a piezoelectric material, when an electric field is exerted to the piezoelectric material to cause deformation, a vibrating film is driven to send sounds. Although a structure of the piezoelectric speaker can be miniaturized and flattened, a sound quality thereof is limited.
Main applications of the electrostatic speakers in the market are hi-end earphones and speakers, and an operation principle of the conventional electrostatic speaker is as followed. Two fixed porous electrodes are used to clamp a vibrating film to form a capacitor, and by supplying a direct current (DC) bias to the vibrating film and supplying an alternating current (AC) voltage of sound frequency to the two fixed porous electrodes, an electrostatic force generated by positive and negative electric fields drives the vibrating film to vibrate, so as to generate sounds. However, the bias of the conventional electrostatic speaker is required to be hundreds to thousands of volts, so that an external high-price and large-size amplifier is required to be connected. Moreover, during a conversion process, a power source of more than 400 volts is required, so that such active driving circuit may have high power consumption, which is not applicable.
Regarding a mass production, individual units have to be fabricated one-by-one according to the conventional technique, and the speakers generally have a fixed size and shape, so that effective mass production cannot be achieved, and cost thereof cannot be reduced. Moreover, soft and thin in appearance and features of low driving voltage and flexibility of the speaker cannot be achieved.